Impact of chronic patency of infarct-related coronary artery on prevalence of myocardial ischemia during the pharmacologic and exercise stress test.
BACKGROUND
Even late restoration of anterograde coronary flow may have beneficial effects on left ventricular function, electrophysiology, and survival in postinfarction patients.


OBJECTIVE
The patency or occlusion of an infarct-related coronary artery in the chronic phase may also be associated with myocardial ischemia provoked by pharmacologic and physiologic stress tests.


METHODS
High-dose dipyridamole echocardiography test (DET) (up to 0.84 mg/kg over 10 min), exercise electrocardiography (EET), and coronary angiographic data in a group of 127 in-hospital patients who had survived an acute myocardial infarction were analyzed. Patients who had only angiographic evidence of infarct-related single artery disease (> or = 50% luminal diameter reduction) and no previous revascularization were enrolled in the study. DET and EET were performed (DET in all, EET in 118 patients) within 5 days before coronary angiography. Fifty-seven patients had total occluded infarct arteries (Group 1) with various degrees of collateral circulation (2.6 +/- 1.1 collateral score, by a 3 grading system), whereas the other 70 patients had patent infarct arteries (Group 2) with significant residual stenoses (82 +/- 13% diameter reduction).


RESULTS
The prevalence of rest angina or effort angina and topography of the infarct-related coronary artery did not differ between the two groups (all p = NS). There were more patients with Q wave in Group 1 than in Group 2 (72 vs. 57%, p = 0.08) compared with non-Q wave infarction (Group 1 = 28 vs. Group 2 = 43%, p = 0.08). Ischemia in the infarct-related artery territory detected by DET (defined as new wall motion dyssynergy or marked worsening of resting hypokinesia) was 61% in Group 1 and 41% in Group 2 (p = 0.025). EET was positive in 26 of 54 (48%) Group 1 and in 21 of 64 (33%) Group 2 patients (p = 0.09).


CONCLUSIONS
Patients with occluded infarct-related arteries have a higher prevalence of ischemia during DET and EET regardless of the presence of collateral flow. These results suggest that the presence of partial anterograde flow in the prolonged period could have a favorable influence on prevalence of residual ischemia in these patients.
Lu
C
C
Cardiovascular Department, Medical School, Pisa University, Italy.
Marzilli
M
M
Distante
A
A
Wang
Y
Y
De Nes
M
M
Marraccini
P
P
L'Abbate
A
A
D001783:Blood Flow Velocity; D003097:Collateral Circulation / Q000502:physiology; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004176:Dipyridamole; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications* / Q000503:physiopathology; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D015995:Prevalence; D015996:Survival Rate; D014654:Vascular Patency / Q000502:physiology; D014665:Vasodilator Agents
D014665:Vasodilator Agents; D004176:Dipyridamole